I. Brain introI. Brain imaging methodsII. Motives: the basicsBrain Imaging Methods:PET (position emission tomography): neural activity inferred from detection of radiation products.Highly invasive (radioactive decay products)MRI (magnetic resonance imaging): Create a picture of brain structures by “reflection” of RF signals. Uses high-strength magnetic fields to align molecules.Detecting regional cerebral blood flowfMRI measure brain activity as well as structure.Determine what parts of the brain detect specific stimulationfMRI shows the difference between the activation of the brain when looking at a reference stimulus and the activation when looking at the specific stimulation being measuredLarge differences appear as hot colorsNeed a control task to compare it to the experimental taskMEG (magnetoencephalography): Detects weak magnetic fields produced by neural activity.EEG (electronencephalography): Measure electrical activity (voltage changes) over cortical surfaces (“evoked potentials”).High temporal resolution, low spatial resolution (limited to cortical surface activity)Sensing electrodes respond to voltage changes over cortical surfaces produced by the electrical activity of the brain. These are then amplified and displayed.rTMS Repetitive Transcranial Magnetic Stimulation: temporary disruption of electrical activity of the brain.Effects the ongoing activity of neurons in the cortexCan shut down activity in part of the brain and reverse it back to normalrTMS can interfere with the function of mirror neurons that are important in learning by imitation; can also be used to selectively disrupt memory store and retrievalSingle-unit recording: Measure activity of small sets of neurons or individual neurons.Not for the use of punishmentStudying sensory coding in the brain- These methods of observing brain activity differ in invasiveness, temporal resolution, and spatial resolution (and cost)g = general intelligenceDifferences in where the brain lights up between people with higher test scores and lower test scoresTracing mental activity with sensing electrodes:Retina  LGN  V1 (simple visual forms, edges, corners)  V2  V4 (intermediate visual forms, feature groups)  PIT  AIT (recognition, meaning, associations)  PFC (categorical judgments, decision making)  PMC  MC (motor command)  to spinal cord  to finger muscleHappens in a quarter of a secondV2, V4 = visual analysisParts of the brain in accordance:•RETINA (regarded as being part of the brain)• LGN: LATERAL GENICULATE NUCLEUS OF THALAMUS•OCCIPITAL LOBES V1-V4 AREAS• TEMPORAL LOBE: POSTERIOR INFERIOR, ANTERIOR INFERIOR• PFC: PREFRONTAL CORTEX• PMC PREMOTOR CORTEX• MOTOR CORTEX• EFFECTORS- Endophenotype: fundamental brain-based response, observable behaviorMotivation: The Basics (new powerpoint)What are the reasons for a behavior?Precipitating external influenceInternal “push” (drive)GoalsIncentives (“pull”)Theories of organisms attempt to explain1) Why organisms are active (energizing of behavior)2) Direction of behavior (goals)3) Nature of reward/reinforcementFundamental motives:- Maximizing pleasure, minimizing pain (hedonism)- Getting genes into the next generation (Dawkins, The Selfish Gene)- Fitness and inclusive fitness- Control of the environment: its resources and other beings in it.- Maintaining homeostasis p. 187-188Staying alive- Drive reductionReducing the strength of a drive you’re experiencing- Feeding, fighting, fleeing, mating (the four f’s)Drive/motivational state: controls what you attend to; can change over time in any directionTypes of drive:REGULATORY: hunger, thirst, body temperature (primary drives)SAFETY: harm avoidance, fear, anger, sleepREPRODUCTIVE: sexual drive, care of youngSOCIAL: friendship, acceptance, approvalEDUCATIVE: play, exploration, curiosity.Drive reduction theory of reinforcement: Behaviors that lead to reduction in the strength of a drive are strengthened/reinforced.Example: A rat has to how learn its way through a maze to find a food reward.• Food deprivation  ‘drive stimuli’• Increased activity, exploratory behavior• Activation of unlearned & learned behaviors• Locate and consume food – drive is reduced• This rewards and reinforces the behavior that led to food.Hypothalamus: involved in hunger, thirst, sleep, stress, sex, reinforcement/reward- LH/VMH: Satiety center- “you’ve had enough” center; tells you when to stop eating- Arcuate nucleus: now thought to be the real “master center of appetite control and weight regulation”; It also contains excitatory and inhibitory systems- Hormonal influences (such as leptin) on hunger; inhibitory influence on hypothalamic feeding centers- stop eating, don’t eat anymorePSYC 100 1st Edition Lecture 8 Outline of Last Lecture I. Brain introOutline of Current Lecture I. Brain imaging methods  II. Motives: the basics Current Lecture Brain Imaging Methods: PET (position emission tomography): neural activity inferred from detection of radiation products.- Highly invasive (radioactive decay products) MRI (magnetic resonance imaging): Create a picture of brain structures by “reflection” of RF signals. Uses high-strength magnetic fields to align molecules. - Detecting regional cerebral blood flow fMRI measure brain activity as well as structure.- Determine what parts of the brain detect specific stimulation - fMRI shows the difference between the activation of the brain when looking at a reference stimulus and the activation when looking at the specific stimulation being measured - Large differences appear as hot colors - Need a control task to compare it to the experimental task  MEG (magnetoencephalography): Detects weak magnetic fields produced by neural activity. EEG (electronencephalography): Measure electrical activity (voltage changes) over cortical surfaces (“evoked potentials”).- High temporal resolution, low spatial resolution (limited to cortical surface activity)- Sensing electrodes respond to voltage changes over cortical surfaces produced by the electrical activity of the brain. These are then amplified and displayed. rTMS Repetitive Transcranial Magnetic Stimulation: temporary disruption of electrical activity of the brain.- Effects the ongoing activity of neurons in the cortex- Can shut down activity in part of the brain and reverse it back to normal -